The Tour de France's attention may be fast switching towards the mountains, but right up until the last moment possible Alessandro Petacchi continued to scoop up the stage wins. And the 29-year-old Italian sprinter's fourth in six days was probably his finest so far.

He zigzagged past the massed ranks of his rival fast men with 300 metres to go and then moved so far ahead on the broad boulevard in central Lyon that he even had time to look back before raising his arms in the air.

If taking four stages so close together in the Tour is remarkable enough, to do so after winning six in the Giro means that, as Petacchi said, he "must be getting into the record books by now". Indeed, only Eddy Merckx, widely held to be the greatest-ever cyclist, managed to take more than 10 in the two events combined - on three occasions. But Petacchi was diplomatic enough to insist that "comparisons can't be made. I'm just a sprinter, Merckx is Merckx."

While Petacchi's Tour now effectively goes on hold until after the mountains, for Lance Armstrong, the rider trying to equal another record held jointly by Merckx, Jacques Anquetil, Miguel Indurain and Bernard Hinault, that of winning five Tours, the race proper begins today - with the Alps.

Armstrong has made it a tradition to attack at the foot of the final climb on the Tour's first day in the mountains, and there is little reason to suppose that he will not do the same again on the first category Col de La Ramaz, the showdown to today's 230.5-kilometre (143-mile) stage. Armstrong is already familiar with the Ramaz, last used in the Tour 21 years ago, but which formed the Dauphine Libéré stage race, an event that the Texan won last June.

Defined by his directeur sportif, Johan Bruyneels, as "extremely difficult", the Ramaz is certainly not for cycling softies, the often unbarriered road swooping ever upwards in broad zigzags for 14km first through pasturelands, then along the edge of a huge cliff face. The finish itself is situated, after a headlong descent through pinewoods, in the nearby ski resort of Morzine.

This is ideal terrain for Armstrong, who is one second behind his team-mate and the race leader, Victor Hugo Peña, but Bruyneels has guessed he may take a more conservative approach than usual.

"It's the first time in three years that we've gone into the mountains ahead of the rest of the field, so this time in principle it's up to us to defend that lead, not attack," he said.

The Ibanesto.com manager, Eusebio Unzue, who directed Miguel Indurain to five Tours, commented. "The situation isn't as bad for the rest of us as it looks. Other years, thanks to the opening time trial, we'd have been five or six minutes down on Armstrong at least by this point, and on this occasion, our team leader, [Francisco] Mancebo is only 90 seconds back."

Other rivals, such as Joseba Beloki and Jan Ullrich are even closer. The Basque is 33 seconds behind Armstrong with the German a further six seconds adrift.

The Alps will prove critical for David Millar, given that this is the first time the Scot is seriously contemplating disputing the overall classification.

"I know the Ramaz really well - too well, in fact, because that's where I punctured in the Dauphine." he said. "But I want to be up there with the other favourites and see how far I can get."

"He's our only leader in Cofidis for the Tour," said Millar's directeur, Francis Van Londersele. "He can do it. He can fight for the overall. It's just a question of self-belief."

But there has been little opportunity for reading the tea-leaves so far as regards what Armstrong, around whom the entire stage - and race - will pivot, may get up to today.

On the Côte des Echarmeaux yesterday, the favourites remained snugly ensconced in the main part of the peloton, while the unknown Australian team worker Matt Wilson, laid down a ferociously tough pace at the front of the bunch.

Wilson's charge was all part of the sprinters teams' successful campaign to pull back a day-long break by Stuart O'Grady and Antony Geslin prior to Petacchi's late charge for the line, a win which has increased his prestige, but is of little concern to Armstrong: another battle in a very different war.